Adjustable auxiliary seat assembly



Oct. 30, 1951 E, w ao H 2,572,874

ADJUSTABLE AUXILIARY SEAT ASSEMBLY Filed April 15, 1949 2 SHEETS'SHEET l I5 1 6'9 6 7 7 I 79 ,9 I f l 93 a l 1 I INVENTOR. EDGAR W, Mac KNIGHT fim 737M157 HIS ATTORNEYS Oct. 30, 195.1 Y E. w. M KNlGHT 2,572,374

ADJUSTABLE AUXILIARY SEAT ASSEMBLY I Filed April 13, 1949 2 SHEETSSHEET 2 IN V EN TOR.

' EDGAR w. Mac KNIGHT H/J A T TORIVEYJ Patented Oct. 30, 1951 UNITED STATES PATENT OFFICE Claims.

My invention relates to adjustable seats and more particularly to a seat assembly for technicians such as dentists, to permit such technicians to operate while comfortably seated. Inasmuch as the present invention was developed primarily for use by dentists while operating on patients, the invention will be described with this application thereof in mind.

Among the objects of my invention are:

(1) To provide a novel and improved adjustable seat assembly, particularly for use by dentists when working on patients;

(2) To provide a novel and improved adjustable seat assembly for dentists which will support a dentist in proper operating position with respect to a patient in a dental chair;

(3) To provide a novel and improved seat assembly for dentists which will permit such dentist to move to any desired position with respect to a patient and Without conscious eifort on his part;

(4) To provide a novel and improved seat assembly for dentists which will permit movement by the dentist to any desired position with respect to a patient, merely through body urging and not requiring the use of the hands which during work on a patient should remain as sterile as possible, under the circumstances;

(5) To provide a novel and improved seat assembly for dentists which provides long linear travel of the seat toward and away from a patient, and Without necessarily causing turning of the seat;

(6) To provide a novel and improved seat assembly for dentists which provides for linear movement toward and away from a patient, without sliding friction;

(7) To provide a novel and improved seat assembly for dentists which is stable under all conditions of use, and not apt to throw or overbalance the user;

('8) To provide a novel and improved seat assembly for dentists which provides linear movement toward and away from a patient, with a minimum of obstruction to free movement of the user;

(9) To provide a novel and improved seat assembly for dentists which can track about a center Within the base of the patients chair, and position the dentist at the best operating locations with respect to the patient.

Additional objects of my invention will be brought out in the following description of a preferred embodiment of. the same taken in conjunction with the accompanying drawings wherein- Figure 1 is a three-dimensional view of a seat assembly embodying the features of the present invention and illustrating one manner of tieing the same in with a patients chair;

Figure 2 is an elevational view in section through the seat assembly of Figure 1;

Figure 3 is a view in section taken in the plane 3'3 of Figure 2;

Figure 4 is a view in section taken in the plan 4-4 of Figure 2;

Figure 5 is a fragmentary view depicting linear movement of the seat;

Figure 6 is a view in section depicting an alternative manner of anchoring the seat assembly to the patients chair;

Figure '7 is a three-dimensional View of a portion of the anchoringmeans of Figure 6'.

The embodiment of the invention as illustrated in the drawings, includes a wheel truck I involving a trough member 3 having depending side walls 5 and 1, and between these side walls, adjacent each end of the trough member, there is weldedor otherwise affixed a depending yoke 9 for mounting a wheel II.

A vertically disposed channel member l3, constituting the outer component of an adjustable telescopic standard [5, has at its lower end, a cross arm in the form of a shallow saddle H which straddles the trough member of the wheel truck and is bolted thereto, thereby providing firm anchorage for the vertical channel member.

This vertical channel supports a bracket IS on which a tongue 2| may be slidably adjusted as to elevation, such bracket constituting a pair of spaced bracket blocks 22 and 23 inserted within the channel member and welded or otherwise" affixed thereto, and to the exposed ends of these two blocks, there is bolted, a bracket plate 25 of a width such that its vertical edges extend slightly beyond the bracket blocks to either side thereof.

The aforementioned tongue 2! involves a length of channel member, preferably slightly tapered for appearance sake, with its broad end toward the bracket plate to which it is adjustably fixed for elevational adjustments. This is accomplished by affixing to each side of the tongue at its broad end, a clamping plate 2'! which overhangs or extends beyond the end of the tongue sufficiently to permit of the formation of a groove 29 adapted to receive an edge of the bracket plate. A clamping bolt 3| passing through the tongue and clamping plates constitutes means for drawing the clamping plates towards each other for clamping the tongue to the bracket plate at any desired position along such bracket plate.

Such vertical adjustment of the tongue permits the seat assembly to be accommodated to chairs of different designs and styles, as placed on the market by different manufacturers, thus enabling the tongue to clear operating pedals, engine rheostat etc., as well as the base flange of the patients chair. Such clearance allows the operator to move in close to the patient.

At its narrow end, the tongue terminates in a pivot yoke 33 having its legs lying in parallel horizontal planes, and perforated to receive a vertically disposed pivot pin 35.

The inner member of the telescopic standard constitutes a tube 31 which carries the seat 39 and associated mechanism 40. It is telescopically supported within the vertical channel member by providing aligned openings in the bracket blocks 22, 23 of a size sufiicient to slidably receive the tube, and at the upper end of the vertical channel member, there is provided means 43 for locking such tube in any vertically adjusted position.

Such means comprises a rectangular housing of two sections, namely, a lower section 45 which is integrally united to the upper end of the vertical channel member, and an upper section 41 which provides a matching fit with the lower section. The upper section is held to the lower section by a bolt 49, both sections having vertically aligned openings to permit passage of the tube 31.

Within the housing is a locking plate which has a central bevelled opening therethrough, through which the tube may comfortably pass when such locking plate is in a horizontal position. At one end, this locking plate is loosely supported between a shoulder 53 and a flange 55 formed by suitably crimping a piece of sheet metal and welding the same into the lower section of the housing, while at its opposite end, the plate is provided with a perforation through which the bolt 49 passes, the plate being normally urged downwardly at this end, against the tube 31 by a compression spring 51 above. Disposed below the locking plate in line with the compression spring 51, is a lip 59 constituting one end of a lever 6|, preferably in the form of a stiff Wire loop which extends through a wall of the housing and fulcrums on the edge of the opening through which it passes. Under the action of the compression spring, the tube will in the absence of any opposing force, remain in its prevailing adjustment, and any weight or pressure applied to the upper end of the tube as when one sits upon the seat, will only serve to enhance the binding effect of the locking plate thereon.

When it is desired to adjust or change the elevational position of seat which is carried on the tube, a downward pressure on the exposed end of the lever, will lift the lower end of the locking plate, thereby bringing the plate to a horizontal plane, whereby the tube will be freed for movement along its vertical axis.

As previously indicated, the tube 31 carries the seat 39 and its associated mechanism 49. Such associated mechanism includes a rod or shaft 63 journalled in bearings 55, 51 disposed, one at each end of the tube. This shaft extends beyond the upper end of the tube and at this end, there is fixedly mounted an arm 69 which terminates at its other end in a bearing 1!, in which is journalled a short shaft 13 which protrudes from the bearing at either end thereof. At its upper 4 end, this short shaft has aflfixed thereto a seat arm 15 in the free end of which is journalled the stem T! of a suitable seat 39, spaced bearings being preferably provided for this purpose.

As thus far described, the path of movement of the seat with respect to the axis of the supporting tube, is indeterminable and not fixed. This is so because, under the circumstances, the seat is adapted to swing indiscriminately about the short shaft as an axis, while at the same time, the short shaft is adapted to swing indiscriminately about the axis of the supporting tube. Therefore in order to pre-establish the permissible path of movement of the seat with respect to the axis of the supporting tube, both of the aforementioned swinging movements must be controlled with respect to each other.

This I accomplish by fixedly mounting on the upper end of the tube, a sun gear 19, while at the lower end of the short shaft 13, I provide a planetary gear 8|, and then connect the two gears by some drive means such as a chain drive 83. With such a connection, any swinging movement on the part of the short shaft in an are about the axis of the supporting tube, will cause the seat to swing in an arc in opposite direction about the short shaft axis.

By selecting a proper relationship between the ratio of arm lengths 69 and 15 and the gear ratio, substantially linear radial movement of the seat may be realized and along a path through the axis of the supporting tube. A gear, ratio of two to one between the sun gear and planetary gear will satisfy the requirements, where both arms are of the same length.

To assure that such linear movement shall be confined to a particular direction, namely, along the axis of the tongue, which will then provide for linear movement toward and away from a patient, the seat and its associated mechanism should be initially assembled so that a line joining the axis of the supporting tube and the center of the seat, shall sight along the axis of thetongue, and to assure maintenance of such directional adjustment, the sun gear must be fixed against rotation on its axis. This is accomplished by affixing a guide rib along the back of the bracket plate 25 and slidably engaging the same by a guide block 81 afiixed to the tube 31.

Extending upwardly from the sun gear, are a pair of stop pins 89, 9| disposed on a line preferably slightly off center. Such stop pins stand in the path of movement of the planetary arm 69 and thus preclude the short shaft from ever reaching a dead center position, which might interfere with smooth effortless movement of the seat. Ease of movement of the seat between its permissible limits will therefore, always be assured.

A shroud 93 may be installed over the planetary gear arrangement, and when so installed, is held out of contact with the chain drive by a bolt 95 extending through the planetary arm.

The entire seat assembly is designed for arcuate travel about the pivot pin 35 located at the end of the tongue, and accordingly to facilitate such movement, the truck wheel yokes 9 are installed on a slight angle so as to cause the Wheels todescribe an are about such pivot point without drag.

Two means are provided for anchoring the seat assembly to the patients chair. One such means may take the form of a band 99 adapted to be adjustably clamped about the base or acme- ,1514

pedestal, I of such chair, such band carrying a; yoke 1.01! with aligned pivot openings, such yoke bein adapted to. straddle the y ke at h end of the tonguefor the reception of the pivot pin, 357..

Another means ofv fastening the seat assembly to. a dental. chair takes, theform of a pivot pos [0.33, nr risionbeing made for anch r he sam to the lower rim I of the base of the patients chair by means of a suitable clamp. Such clamp may involve an arcuate trough section I89 adapted to fit over the rim of the chair base, leaving an exposed upper horizontal flange HI to which may be attached one end of the pivot post.

Such attachment is preferably by way of a ball and socket connection, the rim being raised at the point of connection to provide a socket ll3 while the pivot post, at its point of connection, having a tubular lower end H4 which is threaded internally for the reception of a bolt H5 passing through the flange of the clamp, with its head fitting into the socket. By constricting the neck of the bolt, a certain latitude of movement for the pivot post will be permitted at this point.

By providing a lateral perforation through the lower end of the pivot post to expose certain of the threads on the bolt, and then deforming such threads with a suitable tool, the pivot post connection to the clamp may be made permanent.

The pivot post is preferably made extensible by making it of telescoping parts, namely a pivoted tubular element H4 with a sleeve H9 slidable thereon, and then providing means for supporting the sleeve at different elevational positions on the tubular element. This can be readily accomplished by laterally perforating the pivoted element at spaced points longitudinally, and providing a pair of diametrically disposed openings in the sleeve, which are adapted to line up with selected perforations in the pivoted element. The perforations in the sleeve are preferably of larger diameter than the openings in the pivoted element to receive the head and nut of a clamping bolt I23 passing through the aligned holes, whereby, upon tightening the nut on such bolt, the tightening pressure will be applied solely to the pivoted element, and sufficiently to compress the same and cause corresponding expansion in a normal direction against the sleeve, to thereby bind the same against movement with respect to the pivoted element.

At its upper end, the sleeve is closed except for a threaded axial opening for the reception of a pin or bolt 35. Such bolt is adapted to pass through the perforations in the yoke at the end of the tongue prior to threading the bolt into the upper end of the sleeve for securing the seat assembly to the pivot post. A suitable spacing collar I25 may be applied to the bolt for disposition between the spaced arms of the pivot yoke, to rigidify the connection at this point, so that all pivot movement will occur at the lower end of the pivot post.

The ball and socket pivot connection of the pivot post to the clamp not only provides for the arcuate travel, of the entire seat assembly as indicated, but permits the seat assembly to ride over obstructions or irregularities without transmitting undue strain to any part of the device.

Ordinarily in the average installation, the weight of the patients chair on the lower flange of the clamp Will be sufficient to hold the pivot post installation in place, but in the event such chair should be susceptible to creeping, the upper flange of the clamp. may be provided. with spaced openings for the reception of a pair of clamping screws I21 which may be tightened down against the rim of the base of the chair.

From the above description of my invention in its: preferred form, it will become apparent that the; same fulfills all the objects; of my invention as previously stated, and while I have described my invention in considerable detail, the same is subject to alteration and modification without departing from the underlying principles thereof, and I, therefore, do not desire to be limited in my protection to such details except as may be necessitated by the prior art.

Iclaim:

1. A seat assembly comprising, a wheel truck, a standard extending upwardly from said wheel truck, a seat supported on said standard, a bracket carried by said standard, a tongue connected at one end to said bracket, and pivot means for pivotally anchoring said tongue at its other end to a portion of a dental or similar chair, said pivot means including a pivot post having a clamp loosely connected to an end of said pivot post for anchoring the same to the edge of the base of such chair.

2. A seat assembly comprising, a, wheel truck, a standard extending upwardly from said Wheel truck, a seat supported on said standard, a bracket carried by said standard, a tongue connected at one end to said bracket, and at its other end terminating in a pivot yoke, and pivot means for pivotally anchoring said pivot yoke to a portion of a dental or similar chair, said pivot means including a pivot post having a clamp loosely connected to an end of said pivot post for anchoring the same to the edge of the base of such chair.

3. A seat assembly comprising, a Wheel truck, a standard extending upwardly from said Wheel truck, a seat supported on said standard, a bracket carried by said standard and including a bracket plate, a tongue slidably connected at one end to said bracket plate, and pivot means for pivotally anchoring said tongue at its other end to a portion of a dental or similar chair, said pivot means including a pivot post having a clamp loosely connected to an end of said pivot post for anchoring the same to the edge of the base of such chair.

4. An adjustable seat assembly comprising, a

wheel truck, a telescopic standard extending upwardly from said wheel truck, a seat supported on said standard, a bracket carried by said standard and including a bracket plate, a tongue slidably connected at one end to said bracket plate, and at its other end terminating in a pivot yoke, and pivot means for pivotally anchoring said pivot yoke to a portion of a dental or similar chair, said pivot means including a pivot post having a clamp loosely connected to an end of said pivot post for anchoring the same to the edge of the base of such chair.

5. A seat assembly comprising, a wheel truck, a standard extending upwardly from said wheel truck, a seat supported on said standard, a bracket carried by said standard, and including a vertically disposed plate, a tongue,' and means for adjustably aflixing said tongue to said plate for elevational adjustments.

EDGAR W. MACKN'IGHT.

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